Electronic type reactive power meter

Abstract

Abstract PURPOSE:To improve response characteristics, frequency characteristics, etc. by digitally delaying the output of a pulse width modulating circuit then multiplying the same by load current. CONSTITUTION:The output of a pulse width modulating circuit 8 to which load voltage is supplied from a potential transformer 7 is held by a prescribed time by a delay circuit 8, and is converted to the signal in delayed phase. A delay time detecting circuit 10 transmits a signal at the zero cross time and peak time of a voltage signal, and sets the time corresponding to a phase angle pi/2 to the circuit 9. On the other hand, the consuming current from a current transformer 12 is conducted via a resistance 13 to a time division multiplier 14, the multiplied output whereof is supplied via an integrating circuit 15, a voltage-pulse frequency converting circuit 16, and a frequency dividing circuit 17 to a display circuit 18, by which reactive electric power is displayed. Since the reactive electric power is obtained by digital signal processing in this way, the delay in response is eliminated and the influence of frequencies is eliminated.

Inventors

• 👤 Shunichi Kobayashi

Bibliographic Details